The present invention relates to absorbent articles, and more particularly to absorbent pads for the articles.
In the past, disposable absorbent articles, such as diapers, have been provided with absorbent pads to receive and retain body fluids. In order for the articles to function in a suitable manner, the pads should be capable of transmitting the body fluids from the point of application to remote areas of the pads, thus distributing the fluids throughout the pads and minimizing saturation at the point of application. In addition, the pads should be capable of retaining the body fluids when the pads are placed under loads, else the fluids will leak from ends of the pads.
Particularly in the case of disposable diapers, the pads are normally made from a mass of fibers, such as comminuted wood pulp known as wood fluff. In large part, the fluid holding capacity of such pads is dependent upon the spacings between the pad fibers, and if the interfiber spacings of the pads are reduced in size, the capability of the pads for retaining fluids is correspondingly lessened. Alternatively, pads having smaller interfiber spacings provide greater fluid absorption and transmission rates than pads having larger interfiber spacings.
Some of the diapers have been made with pads which are compressed to a relatively high degree throughout the pads. Although the pads of such diapers may spread fluid throughout the pads, the diapers are unsatisfactory since their pads are not capable of retaining a sufficient quantity of body fluids, and thus leak. Also, the pads of such diapers are relatively stiff, and do not readily conform to the shape of the infant. Other diapers have been made with pads which are relatively uncompressed throughout the pads, but such pads are not capable of adequately distributing fluids in the pads.
In an attempt to solve these problems, some diapers have been provided with pads which are compressed to a reduced thickness in certain parts of the pads to provide relatively dense and undense portions of the pads. In theory, the compressed parts of the pads should distribute fluids to spaced portions of the pads, while the uncompressed parts of the pads should retain fluids. However, when such pads are placed under loads during use, the pads permit the originally undensified portions of the pads to be compressed, thus significantly reducing the interfiber spacings in the uncompressed parts of the pads. Accordingly, such loaded pad portions are effectively reformed into densified portions, such that the fluid holding capacity of the pads is impaired and resulting in possible leakage from the pads.